/*
 * Copyright (c) 2024 Huawei Device Co., Ltd.
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

import { ts, rule } from "qvog-dsl";

const SEVERITY = 2;
const DOC_PATH = 'docs/no-uninitialized-const.md';
const DESCRIPTION = 'Const declarations must be initialized at the time of declaration because const variables cannot be reassigned later.';

export default rule()
  .match(ts.isVariableDeclaration)
  .when(node => {
      // 1. 确保是 const 声明
      if (node.parent && ts.isVariableDeclarationList(node.parent)) {
          const isConst = (node.parent.flags & ts.NodeFlags.Const) !== 0;
          if (!isConst) return false;

          // 2. 排除掉 for (const i in/of ...) 里的 const
          const parent = node.parent.parent;
          if (parent && (ts.isForInStatement(parent) || ts.isForOfStatement(parent))) {
              return false;
          }

          // 3. const 没有 initializer 就报错
          return !node.initializer;
      }
      return false;
  })
  .report({
      severity: SEVERITY,
      description: DESCRIPTION,
      docPath: DOC_PATH,
  });
